I have been having this problem with my jeep. It comes and goes so I am having a really hard time figuring it out. For what ever reason, the fuel pump quits working. It is a new single action glass bowl pump from Walcks 4WD. I did have a bunch of junk in the tank plug the suction tube up, which I cleaned out. When it stops pumping, I have to pour some gas in the pump and a little down the carburetor. I usually have to do this 2 or 3 times before it starts pumping again. The gas cap vent seems to be working fine. When I rebuilt the engine, the cam lobe for the pump wasn't worn at all. So, do you guys think the fuel pump got wounded when the line was plugged up?